ANCIENT JERUSALEMITS WATER SUPPLY AND POPULATION*

JOHN WILKINSONThe Plates for this article are between pages 76 and 77

Latin and Greek writers speak ofJerusalem as a large city, well supplied with water.! Yet, as iswell known, there is only one strong spring nearby, and the city could never have grown unlesswater had been brought in from elsewhere. It is the purpose of this article to examine thedevelopment of the ancient water-systems, and to ask what light they may shed on the growthof the population. Such an examination may serve as an additional control for some of theevidence for population numbers recently discussed by Mr Anthony Byatt,2 even though, inthe nature of our enquiry, we are unlikely to obtain final figures which are more thanapproximations.

GIHONHuman beings first chose to settle on the site of Jerusalem because of the abundant springcalled Gihon, 'Ain Umm el Daraj, or the Virgin's Fountain. Nearby there is another spring, EnRogel or Bir 'Ayyub, but this would hardly have played a decisive part in deciding the site of thefuture city, since its yield is small and it is hard to defend. Gihon itself is not easy to defend, butit is extremely productive.3 Even its minimum yield would provide two buckets of water a dayeach for a population of 10,000 persons,4 but this does not mean that there were ever as manyas 10,000 in Jerusalem when it still depended on Gihon alone. The spring has today beenhidden by the accumulation of soil in the bottom of the Kidron Valley, but even when it wasstill above the level of the valley floor it was in an unusually awkward position. Its naturaloutflow would no doubt have provided good irrigation, but the water available for domesticuse was only the amount the inhabitants were able to draw before it flowed away to waste,5 or,at the most, about a quarter. It would be absurd to think that the citizens of Jerusalem drewtheir water with rigid discipline all day and all night, and we must therefore agree withProfessor Amiran's judgement that Gihon could effectively serve only 'the needs of a good-sizedvillage'.6 So long as Jerusalem depended on its single spring it can hardly have had more than2,500 inhabitants,7 an estimate which agrees well with its small area (see Fig. 1 (1)).8

* The author is most grateful to ProfessorAmiran, andalso to ProfessorsJames Barr and R. M. Grant, MissMumia Sa'id and P. H. Stem, Esq, for advice in pre-paring this article.

1See L. H. Vincent and M. H. Steve, Jerusalem de['Ancien Testament, Vol. I (Paris 1954), 297f.

2 A. Byatt, 'josephus and Population Numbers inFirst Century Palestine', PEQ 105 (1973), 51-60.

3 Its minimum yield is 73,000cu.m. per year, and itsmaximum over five times as great: seeD. H. K. Amiranin B. Mazar and others, Jerusalem, the Saga of the Holy .Ciry (Jerusalem 1954), 45.

4 Two buckets contain about twenty litres, whichwould be a low estimate for daily consumption. Com-pare the following: three litres per head per day inLebanon (recent survival test); fifteenin Madrid (1888);

sixteen in Jerusalem (1925); twenty in villages inLiberia (1972); thirty in Barcelona (1888); thirty-six invillages in S.E. Ghana (1970); ninety-one in standpipesin South Africa (1970); 204 in England and Wales(1970); 227 in Scotland (1970); and 363 in the U.S.A.(197°)·

5 The small pool marked by the letters Land M inR. Weill, La Cite de David (Paris 1920),46, seemsto havebeen the earliest arrangement to make it easier to drawfrom Gihon, but it could not have stored the water inany significant quantity.

6 Amiran, Ope cit., 45.7 We here assume a consumption from city supplies

of twenty litres per head per day. The product ofcisterns is discussed below, p. 47.

8 See K. Kenyon, Jerusalem (London 1967), 29.

1 KM.

Fig. I. The Area of the CityI. Under theJebusites and David 2. Under Solomon 3. In the Late Monarchy

Fig. 2. The Hill-side channel from Gihon.

150 M.

PALESTINE EXPLORATION Q.UARTERLY

In war time Gihon became even more inconvenient, since the citizens could only reachtheir water by an underground system of tunnels, known by its excavators as 'The DragonShaft'.9 The water from the spring was led into the hillside to the bottom of a well, and fromground-level inside the city walls a staircase and rock gallery were cut to connect with the well-head. This system cannot have remained useful when the city began to expand, and we maytherefore assume that an alternative arrangement had been made by the time Solomon'sreign was over, since during that period the city area was more than doubled. (See Fig. I (2)).10

The new system offered considerable advantages over the Dragon Shaft. It comprised achannel cut in the hill-side (see Fig. 2, A-B and Plate VIlA), which led from Gihon to a receiv-ing pool at the southern tip of the city, which is now called Birket ell:Iamra.ll Besides providingfor irrigation12 the new channel and pool made it far easier to draw and store the water fromthe spring, and we may guess that the number of persons able to use it could have doubled.But it was hard to defend, and though we may guess at possible courses for walls which mayhave surrounded it (as in Fig. 2, (Z)) we cannot yet say for certain what protection it had.13

THE ETAM SYSTEMBy enlarging Jerusalem and raising its standard of living King Solomon increased the need forwater. Should we therefore accept the tradition that he was the maker of 'Solomon's Pools'?The traditional name describes three reservoirs which receive the water of some strong springs11.5 km. south ofJerusalem,14 which are in fact the nearest large supply of water at an altitudegreater than that of the city, and are connected with Jerusalem by aqueduct. Its channel runspast Khirbet el Khokh,15 and along the eastern slopes of the main ridge like a contour line (seeFig. 3) till it reaches the west side of the Valley of Hinnom.16 Crossing the valley above Birketes Sultan it passes round Mount Sion (see Plate VIllA), and runs along the city wall (see PlateVIIIB) till it passes through it about 100 metres west of the Dung Gate. From this point ittravelled north to Wilson's Arch, over which it was carried into the l:Iaram esh Sherif.17 Thetotal length of the channel is 22.5 kilometres.ls

A relatively late tradition that Solomon made 'pools from which to water the growing trees'is to be found in Eccles. 2 :6, and Josephus describes Solomon's chariot excursions to Etam.19Indeed the pools at Etam are first said to be his only in the Talmud.20 But though ourdocuments are inconclusive we may reasonably regard at least one of the pools and the aque-

9 See H. v. [alias L. H. Vincent] UndergroundJerusalem (London 191I), 12,plates 3a and b. The shaftwas associated by its excavators with the 'tunnel' bywhich they believed that Joab climbed up to capturethe city. But neither the obscure phrasing of 2 Sam. 5: 8nor I Chron. I I :6 demand the existence of such atunnel, as evidenced by the translations of these versesin the LXX and N.E.B.

10 K. Kenyon, Opecit., 57.11 This would thus be the first 'Pool of Siloam': see

Isa. 8 :6, and compare J. Simons, Jerusalem of the OldTestament (Leiden 1952), 167f.

12 Through the short eastern channel and outletsfrom the ma in channel.

13 K. Kenyon, Opecit, 69, 71 and 77 proposes adifferent arrangement: contrast P. Benoit, RB (1969),264-5.

14 Their combined yield is 73,000 cU.m. per year(Amiran, lococit.). The three springs called 'Uyun ~alil;1,el Faruja, and 'Atan are shown in SWP III, 89 and byC. Schick, 'Die Wasserversorgungder Stadt Jerusalem',ZDPV I (1878), plan facing 176, but these two

authorities disagree over the position of the fourthspring.

15 The site of biblical Etam. For the course of theaqueduct see the new survey by A. Mazar, 'TheAncient Aqueducts ofJerusalem', (Hebrew), Qadmoniot5 (1972), 120-4 and map.

16 It is displayed in front of the Montefiore cottages.17 See G. Adam Smith, Atlas of the Historical

Geography of the Holy Land (London 1915), map 49-50.18 The fall of the channel is 38 m, resulting in a

gradient of I: 3,125. This would have produced a rapidflowlikely to have worn the sides of the channel, whichwould account for the many re-linings and repairsvisible on the remaining sectionsof this aqueduct. Mostof the earthenware pipes in the aqueduct were placed inthe channel in the seventeenth century, and the lastknown repair was made in anticipation of KaiserWilhelm's visit (see D. Yellin, Hamelitz, May 1898). In1902 the Turkish Government is said to have installedmetal pipes to replace the old aqueduct between thetunnel below Bethlehem and Jerusalem.

19 Ant.8.186: cf. S. ofS. 3: 6-10. 20 Zebaim 54b.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 37duct as products of the Israelite monarchy. To survey and construct a system of this kind is alarge undertaking, but does not require any skills which cannot have been available in thatperiod, as any farmer knows who has made field-drains. It is therefore an attractive possibilitythat Ahaz met Isaiah beside this very aqueduct, described as 'the conduit of the upper pool' inIsa. 7:3. In this case the pool was probably somewhere in the Temple area, and the implied'lower pool' would have been Birket el I:Iamra, with the conduit from Gihon. The enlargementin the water-supply probably accompanied the increase in city area implied by the broad walldiscovered by Professor Avigad,21 which was built in the late monarchy (see Fig. I (3)).

ETAM

5KM.

Fig. 3. The Etam System.

HEZEKIAH'S TUNNELAhaz was succeeded by Hezekiah, a king whose memory was honoured partly because he 'madethe pool and the conduit, and brought water into the city' (2 Kings 20:20).22 Yet his famoustunnel, while certainly an improvement on the hillside channel from a defensive standpoint,did not necessarily increase the amount of water available in the city. A passage in Chronicles,which may well have been based on annals in the royal archives, expands on the words we havequoted, saying that Hezekiah 'planned to stop the water of the springs that were outside thecity' (which we take to mean Gihon) ... 'And they stopped all the springs, and the brookwhich flowed through the land' (which we take to mean the hillside channel), 'saying, "Whyshould the kings of Assyria come and find much water?" , (2 Chron. 32: 3-4). Later in the samepassage we are told that Hezekiah 'closed the upper outlet of the water of Gihon and directedthem down to the west side of the city'.23 Whatever the theological overtones of this account24

21 SeeN. Avigad, IE] 20 (1970), 129. Our suggested has found no parts of this aqueduct which he wouldline for the city wall followshis conjectural wall I, and date earlier than the Second Temple period.the outline most recently published in Qadmoniot 5 22 Compare Ecc1us.48: I 7.(1972),94. A. Mazar, Ope cit., 123, showsa photograph of 232 Chron. 32: 30, compare Isa. 22: 9-11•a tunnel forming part of the Etam aqueduct which looks 24 See P. R. Ackroyd, I and II Chronicles, Ezra,very like a section of Hezekiah's tunnel. It may per- Nehemiah, Torch Commentary (London 1973), 190ff.haps belong to the same general period, though Mazar

PALESTINE EXPLORATION Q,UARTERLY

its information corresponds precisely with the archaeological discoveries,25 and we may there-fore safely assume that the hillside channel and Birket el I:Iamra were already in existencebefore Hezekiah came to the throne in 742 B.C., and that he replaced the channel by his tunnelbetween 705 and 701 B.C., as a defensive measure on the eve of the Assyrian invasion.

THE 'ARRUB EXTENSION

At some stage in the Second Temple period the Etam system proved inadequate to the needs ofJerusalem, and was extended southwards to 'Arrub (see Fig. 4). The pool at 'Arrub (see Plate

JERUSALEM

:::;t~ HERODlUM5 KM.

Fig. 4. The 'Arrub Extension and the Herodium aqueduct.

lXA), which collected thewater of three strong springs,26 was eight kilometres beyond Etam,but the new aqueduct meandered so violently that it had a total length of 44.7 kilometres,despite the inclusion of a bridge (Plate XA) and tunnels (Plate XIA)27 to reduce the length asfar as possible. Etam now became the regulating-point for the complete system, and it isprobable that the original lower pool was enlarged and the middle pool constructed at this timeas a means of contro1.28

Though we do not know the exact date of the 'Arrub extension, there is another datedaqueduct nearby. In 25-24 B.C. the droughts in Judaea were so severe that they caused plagueand famine,29 and Herod the Great immediately took steps to provide relief. Then in 23 B.C.,

perhaps to ensure employment for some of those who had suffered, he began building twopalaces, one in the Upper City of Jerusalem, 30 and the other at Herodium, where, according toJosephus, there were pleasure grounds 'worth seeing because of the way in which water, which

25 H. V., op.cit., 31.26 'Ain 'Arrub (at Birket 'Arrub), 'Ain Kuweiziba,

and Bir Kufin.27 A. Mazar, Ope cit., (map) showsthe bridge in Wadi

elJi~r, ref. 1668 1186, and the tunnels at reff. 1679 1143,1680 I 150, and 1682 120 I. He identifies the masonry ofthe extension (see Plates XB and XIA) as belonging tothe Second Temple period, Ope cit., 122.

28 A. Mazar, Ope cit., 123 reports that the supply fromthe springs was improved in Roman times. F.-M. Abel,Geographie de la Palestine (Paris 1933), Vol. I, 453

suggests that the third pool may have been built only inA.D. 1480-3 by Sultan Qait-Bay, since a documentmentions the existence of only two of the pools in 1469.In any case it seems unlikely that the upper pool waspart of the Low-level Aqueduct, since it is at a higherlevel. We may therefore guess that when the section ofthe High-level Aqueduct between Etam and Jerusalemno longer functioned, the upper pool had to be made toreceive the product of Bir el Daraj. See below, pp.45f.

29 Josephus, Ant. 15.299-304. 30 Ibid. 318•

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION '39is lacking in that place, is brought in from a distance at great expense'. 31 Herod's effectivefamine relief won him unusual popularity, but he stood to lose it if he could be accused ofsupplying his palaces with water at the expense of the systems serving the city of Jerusalem.Such an accusation would have been easy to contrive, since the aqueduct for Herodium camefrom 'Artas,32 very close to the one from Etam of which it may even have been a branch (seeFig. 4). There is thus good reason for Herod to have improved the supply to the city in 23 B.C.

The whole system from 'Arrub to Jerusalem, now known as the Low-level Aqueduct,covers a direct distance of 19.3 km. with a channel 67 km. in length, and supplied the LowerCity of Jerusalem of Herodian times: indeed it is possible that the distribution channels of thisaqueduct, traceable at the beginning of this century33 (see Fig. 5) are some of them ~ven older,and witness to the continuing importance of this system for more than two thousand years. Inthe Israelite Temple it supplied the High Priest's ritual bath and the Sea ofBrass,34 and at thebeginning of the Ottoman period it was supplying at least four of the city fountains installed bySuleiman the Magnificent.3s But it is probable that the southern section of the system, between'Arrub and Etam went out of use long before the Ottomans, since it has in many placesdisappeared, and that the much-repaired northern section from Etam to Jerusalem36 is theonly part to have been in use for the past thousand years.

RAIN-COLLECT·ING POOLSThe land to the north and west of Jerusalem rises higher than the city within the walls, andthus provided the potential for a considerable water supply. In four of the valleys in this areaancient pools are (or have recently been) visible (see Fig. 6) which were clearly intended t~collect rain from their surrounding catchment areas (see Fig. 7), and since the pools are allhigh enough to supply the city, we shall for our present purposes assume that this was theirfunction, even though it is not yet clear where all the connecting channels ran .. Equally it isclear that two of the surviving ancient pools37 could never have collected much rain, since theyare sited on spurs.

It is possible that the first rain-collecting pools had already been constructed in the periodof the Late Monarchy,38 but there are no clear literary references to them. In the Hellenisticperiod we hear of a pool which may have been designed for this purpose, since Ecclus. 50: 3informs us that in the days of Simon, son ofOnias (i.e. in about 200 B.C.) 'a cistern for water wasquarried out, a reservoir like the sea in circumference', 39 but we cannot identify it. In hisaccount of Titus' siege of Jerusalem in A.D. 70 Josephus mentions three pools. The first, whichhe calls the 'Strouthion',4o was perhaps made by Hyrcanus I in about 134 B.C. to provide thesupply for his fort, the Baris, and the others, the 'Amygdalon'41 and the 'Serpents' Poo1'42 werein existence at latest by the time of the siege.

Fortunately we do not for our present purposes need to know how all these pools were

31 Ibid. 323-6.32 See the map in A. Mazar, Opecit., nos. 3D-33.33 See G. A. Smith, loco cit. The direction of the

supply-pipe of Birket el Hijja suggests that it was con-nected with the Low-level system, pace Vincent andSteve, Opecit., 303.

34 According to Talmud (Y)Toma 3.8, (B)Toma 31a.35 A.D. 1536-7.36 The water from Bir el Daraj (seebelow, pp. 45f.)

was later diverted into this section, and augmented thesupply from the Etam springs.

37 Birket l:Iammam el Batrak and Birket l:IammamSitti Miriam: the form of the names (Pool of the Bathof ••• ) suggests a similarity.

38 'The Dragon's Well' of Neh. 2 :13 could be thesame as Josephus' 'Serpents' Pool' below, as suggestedby Vincent and Steve, Opecit., 299.

39 A. Duprez, Jesus et les Dieux Guerisseurs (Paris1970), 36, suggests that this may have been theProbatica.

40 War 5.467. SeeVincent and Steve,Opecit., 300 andP. Benoit, 'L'Antonia d'Herode Ie Grand et Ie Forumoriental d'Aelia Capitolina', Harvard Theological Review64 (1971), 139-58.

41 War 5.468. Now Birket 1:1. el Batrak, Vincent andSteve, Opecit., 300.

42 War 5.108. Now Birket es Sultan, Vincent andSteve, Opecit., 299.

400 M.

Fig. 5. Distribution Channels connected with the Low-level AqueductI. Fountain in Hospice adjoining et Takiya 5. Birket Hijja (?)2. Fountain in Tariq el Wad 6. El Kas3. Fountain at Bab ~itta 7. 'The Great Sea'4. Fountain in Tariq el Wad (?) 8. Fountain on south wall of Birket es Sultan.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 41

1 KM.- - IFig. 6. Some ancient pools near Jerusalem, with landmarks

POOLS: I. Birket I:Iammam Sitti Miriam; 2. Probatica; 3. Birket Isra'il; 4. Strouthion;5. Birket el Miya'a; 6. Amygdalon (now Birket I:Iammam el Batrak); 7. Birket es Sultan;8. Birket Mamilla; 9. Birket I:Iusseini; 10. Possible site for a North-West Pool.

LANDMARKS: A. National Palace Hotel; B. Sheikh Jarrah Mosque; C. District HealthOffice; D. Academy of Medicine, Prophets' Street; E. Russian Cathedral; F. King DavidHotel; G. Ratisbonne Convent; H. The Knesset Building; J. Monastery of the Cross.

connected with each other, since we are concerned with their overall product and its effect onthe population of the city. Ifwe make the assumption that rainfall in the Jerusalem area has notchanged since the pools were made,43 we can make a reasonable guess at the total amount they

43 See the working figures in Table 2, p. 51 below. volume falling in the catchment area. This estimateWe take rainfall in the Jerusalem area to have been 600 agreeswith the observation by D. H. K. Amiran, Ope cit.,rom. per year (seeAtlas of Israel (Jerusalem/Amsterdam 50, that in 1953 Birket Mamilla 'fills to the brim almost1970), Map IV/2.A) and the run-off coefficient (the every season', which implies that the pool received 33proportion of the total rainfall actually running into per cent of the total rainfall.the collection pool) to have been thirty per cent of the

PALESTINE EXPLORATION Q,UARTERLY

1 KM.-----BIRKEl EL MIYAA

Fig. 7. Catchment areas near Jerusalem.

would have supplied.44 In some cases, however, it is possible to envisage the way a systemmay have grown, even though in the present state of our archaeological knowledge it is not easyto be sure about chronology.

Since the Upper City was already enclosed by a wall in 165 B.C. we may suppose that BirketMamilla was constructed to supply it with water.45 But the pool sets us an interesting problem,

44 Lossesoccurred through evaporation and leakage.Gross annual evaporation in the Jerusalem area iscalculated at 1.6 metres (see Atlas of Israel, Map IV!3.T) : since rain fell into all surface water the net annualfigure for this loss is I metre. Leakage is assumed to be25 per cent of intake for the longest system and less forthose which were shorter: see Table 2, p. 51 below.

45 G. A. Smith, lococit., showsthe channel connectingBirket Mamilla with Birket J;Iammam el Ba!rak, butthis was only one element in what must have been amore complex distribution system. C. N. Johns, PEQ(1941),52 describes a pipe laid after A.D.70which thenformed part of it, and no doubt succeeded some morelavish method of supply devised for Herod's Palace inthe Citadel area: seeJosephus, War, 5.181,304.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 43since it is almost twice as large46 as it would need to be47 if it was simply to receive and deliverthe rain run-off from its catchment area. It is possible that it was made this size so that it couldstore water, but it is also possible that Mamilla received additional water from some othersource.

The 'Serpents' Pool' gets its present name, Birket es Sultan, either from Suleiman theMagnificent, who adorned it with a fountain in A.D. 1536/7, or from Barquq (1398/9) who isknown to have restored it.48 It is also known that the Teutonic Knights had restored it in theI 170s. But it seems probable that the pool grew to its present size in ancient times. In its firstphase its capacity corresponded very closely with the rain run-off it would have received,49 andeven though no trace of an aqueduct has yet been found it is hard to believe that the pool wasnot connected with the Lower City in the way suggested in Fig. 8. In its second phase itscapacity was doubled, which raises the same problems exemplified by Mamilla.

Though the Amygdalon, the present Birket J:Iammam el Batrak, was at some stage con-nected with Mamilla, its main supply probably came through an aqueduct which runs into thenorth-west corner of the present walled city.50 The other end of this aqueduct seems to lead to avery small catchment area near Mahane Yehuda, but there was probably another branchleading towards the more useful catchment area near Romema which we have indicated as apossibility on Fig. 8.51 The Amygdalon alone would hold only about half the product of theseareas, but it is possible that there were collecting pools which would have stored the water aswell as feeding the aqueduct, and the whole system must have been in operation before A.D. 70.52

The suburb called -Bethzatha,53 immediately to the north of the Temple area, was in theearliest stage of its development probably served by a pool in the position of the present southpool of the Probatica, which collected rain run-off. But the catchment area was only largeenough to supply about 2,750 people, and if such a pool ever existed it would have hardlyremained adequate for long. Whether or not there was an earlier pool at the site, the presentpools are clearly intended to receive more water than the catchment area could supply. It seemsevident that the extra water was brought by aqueduct54 from Birket el Miya'a (see Fig. 8), andit was distributed through Birket J:Iammam Sitti Miriam not only to the Probatica, but also thatto Birket Isra'il. Since Birket Isra'il seems to have been constructed in conjunction with thenorth wall of the Temple area we may guess that the whole system was completed by Herod theGreat when he was enlarging the Temple area between 18 and 10 B.C.55

Since the total capacity of the system agrees well with the rain run-off in the catchmentareas, we should probably envisage the function of the pools as follows. Birket el Miya 'a

46 SeeTable 2, p. 51 below. Capacities there shownare based on the following: for B. Mamilla, C. Schick,PEQ (18g8), 226; for present B. es Sultan ibid, and itsearlier phase, C. Schick, PE'Q (18g8), 227f; for theProbatica north pool N. Van Der Vliet, Ste Marie OUelle est Nee et la Piscine Probatique (Paris I938), Igof; forthe Probatica south pool Duprez, Ope cit, 34; for theStrouthion M.-Aline de Sion, La Forteresse Antonia aJerusalem et la questiondu Pretoire (Jerusalem I956), pI. 22;and for Birket el Miya'a C. Schick, PEQ (18g2), 9-13.Other capacities are based on the SWP and D. H. K.Amiran, Ope cit.

47 The last heavy rain in Jerusalem may fall inMarch, and be the last till November. Thus theminimum size for a rain-collecting pool to serve the citymust be two-thirds of the volume of rain/run-off fromits catchment area, so that it can store enough for eightrainless months.

48 See Amiran, Ope cit., 50, and Vincent and Steve,

Ope cit, 302.49 It held 58,400 cu.m, and two-thirds of the run-off

amounts to 60,000.50 See C. Schick, PEQ (18g1), 278-80.51 Note that no trace of a Romema branch has been

found.52 Notwithstanding the probability that the aque-

duct in its present form seems to be Byzantine.53 John 5: 2; Josephus, War 5.108.54 C. W. Wilson, Ordnance Survey of Jerusalem

(Southampton 1856), Vol. I, 79, and C. Schick, PEQ(18g2), 9-13. The pool (now buried) is in the upperKidron Valley, about 100 metres west of the NablusRoad at map ref. 17165 13315, and a section of theaqueduct is visible '325 feet east of Burj el Laqlaq, cutby the road'.

55 Compare Josephus War 1.401and Ant. 15.380. Ifthere was an earlier pool it was probably constructed inabout 200 B.C.: see Duprez, Ope cit., 37.

44 PALESTINE EXPLORATION Q,UARTERLY

BIRKET EL M IYA 'A

ROMEMAflJ-- ..•.,

.•.•. .•.•.,,,"'

BIRKElHUSSEINf,

\," ,

\\IIf, I\ \l ",I '_,~ ,I II I\ }I .1'- •...•..""., BIR KET,_........ I ,.-

,'" ," ES SULTAN" (I ,, \I ,

t· ....,. ..•---,,-- .......•.. .-

Fig. 8. The Water-systems near Jerusalem.

1 KM.- --

BIRKETHAMMAM

51TTI MIRIAM

BIRKET EL HAMRA

-SIR 'AYUB

received the run-offfrom the upper Kidron Valley, and sent it by aqueduct to Birket I:JammamSitti Miriam, where it settled. At the same time the north pool at the Probatica was receivingthe run-off from its own catchment area, and allowing it to settle. From the north pool there isan outlet channel running beneath the south pool56which forks, one branch continuing south-wards towards Birket Isra'il, and the other east, whose destination is unknown. The immediatedestination of the run-off collected in the north pool therefore seems to have been Birket Isra'iI,whilst the supply fed through Birket l:Iammam Sitti Miriam was probably received aftersettling into the south pool of the Probatica57 and also into Birket Isra'il. It is hard to imagine

56 See Duprez, Ope cit., p. 34.57 Such an arrangement would account for the fact

that Eusebius could see 'reddish' water in one pool (no

doubt the northern settling pool receiving the directrun-off) and 'rainwater' in the other, Onomasticon(Klostermann), 58, lines 23f.

ANCIENT JERUSALE:M: ITS WATER SUPPLY AND POPULATION 45how the water from these pools could have been led into the Temple area, since their level isso low,58 and it is more likely that aqueducts were made to lead some of the water they con-tained to some part of the Lower City, perhaps near the Double Gate of the Temple. Thissupposition is strengthened by the fact that the Bethzatha area, which covered less than one-eighth of the area within the walls after the time of Herod Agrippa, would have been receivingnearly one-third of the city's .water supply unless some of the water was destined for useelsewhere. I

Birket I:Iusseini59may well have been deep enough to provide storage for most of thewater it collected. I~ as suggested on Fig. 8, it was connected with the city, it may havedelivered through Mamilla, but since no connecting channel has been found there are manyother possibilities open. We have included the product of this pool in our figures, though thedate of its original construction is unknown, and may be as late as the third century A.D.60

The Strouthion ('The Swallow') seems to have been designed to serve the needs of thegarrison in the Baris, the fortress later re-named Antonia,61 since it appears to have had a verysmall catchment area, and is unlikely to have served more than about 1,000 people.

The overriding importance of Gihon and Siloam belonged to the period before the con-struction of the Low-level Aqueduct, and of Birket es Sultan, if we are right in surmising thatthis supplied the Lower City. In the Hellenistic city the low altitude and remote position ofSiloam probably meant that except for those living in its immediate neighbourhood itsfunction was largely ornamentaL

THE HIGH-LEVEL AQ,UEDUCTProbably the last major external source to be harnessed to the needs of ancient Jerusalem wasBir el Daraj, fifteen kilometres to the south.62 Its aqueduct begins as a tunnel (see Fig. 9)stretching the greater part of the way to Etam below the Wadi el Biyar (The Valley of Wells),so called because of the regular shafts visible along its bottom (Plate XIA). Mter a shortjourney in the open it passes under a saddle in a second tunnel and runs round the Etam poolsat a level roughly twenty metres higher than the Low-level channel. Two kilometres furthereast its course is lost, but nearly three kilometres further north it re-appears, descendingtowards Rachel's Tomb in a massive stone pipe63 (Plate XII A and B). The pressure thuscreated enabled the water to rise high enough to cross the saddle between Tantur and MarElias Monastery before continuing its descent to Jerusalem, but its course is again lost three

58 Eusebius (loc. cit.) connects the reddish water withthe Temple sacrifices,which could reflect a connectionbetween the Probatica and the Temple. But the bottomof the Probatica north pool is at about the same level asthe floor of 'Solomon's Stables', and the bottom ofBirket Isra'il, when it was visible, was the lowest pointwithin the present walled city.

59 See C. Schick, PEQ (1895), 109. The pool istoday concealed by Gan Sacher, but was examined byDr L. Y. Rahmani on behalf of the Department ofAntiquities before it was covered.

60 I am grateful to Dr Rahmani for this information.61 Josephus, War 5.467. The aqueduct which

supplied it runs under the present 'Aqabat esh SheikhRihan towards the Damascus Gate, where it turnsnorth-east (seeG. A. Smith, Opecit., map 51). Its catch-ment area may have been in the shallow depressionwhich includes the present Y.M.C.A. (East), theEcole Biblique, and Schmidt's Girls' School. Note thatthere is a deeper depression to the west of the DamascusGate, which seems to have been known in Crusader

times as the 'Lac Leger' (seeVincent and Steve, Opecit.,302f.), and therefore to have been used for water-collection, but the destination of its water is at presentunknown.

62 Map ref. 1638 1195, see A. Mazar, Opecit., map.For its yield in 1931see A. Koch, Eighth/Tenth AnnualReport on the Operation of the Jerusalem Water Supply(Jerusalem 1932),whichwasnot available to the presentauthor at the time of writing. The yield was sup-plemented by seepage from the soft bed-rock of thethree-kilometre tunnel leading from the spring (seeMazar Opecit., 123) but the amount thus added is un-known to the present author, and has not been includedin the calculations in Table 2, p. 5I.

63 The bore of 40 em. diameter is enclosedwithin asection I m. square, and each pipe is about 60 em. long.A similar siphon system (in large earthenware pipes),presumably constructed by Herod the Great, is to beseen in the part of the aqueduct to Cyproswhich crossesthe Turkish road to Jericho at map ref. 18801375.

46 PALESTINE EXPLORATION Q.UARTERLY

kilometres south of the city. 64Under the arrangements we have so far envisaged the water mayhave been fed into the city through Mamilla (even though a newly discovered channel whichmay belong to this aqueduct is at a lower level).65 We should therefore regard the High-levelaqueduct as feeding direct into the Upper City, but overflowing when necessary into Birket esSultan, which may have been enlarged to serve this purpose. 66

~RRUB

SIR ELDARAJ

5 KM.

MAMILLA, ,..,..:J~ -"\ <:::::::::. .••JERUSALEM

~N

~:~HERODIUM

Fig. 9. The High-level Aqueduct.

In A.D. 70, we are told, the rebels destroyed 'the canal from Etam', 67a phrase which mightby itself denote either the High or the Low-level aqueduct. But since as a result of the rebels'action the water failed in the Upper City, it seems clear that this Talmud passage refers to theHigh-level system, whose date we must therefore seek in the Second Temple period.

Although we remain ignorant of all the connecting channels from the High-level Aqueduct,we would expect a system of this sophistication to supply the Upper City, whether or not theTalmud is reporting correctly the situation in A.D. 70. The inscriptions connected with theaqueduct are all later, but may record repairs,68 and it remains possible that this wasthe aqueduct built by Pontius Pilate soon after A.D. 26.69 For the purposes of the Tables belowwe shall assume this date.

CALCULATING THE POPULATION

Our study of the Jerusalem water-supply has led us to make a good many conjectures, but incalculating the population we have to make more. Such a predicament is, however, the lot ofthose who set out to interpret the kind of evidence available. Thus there are some cities for

64 See Mazar, Ope cit., map ref. 17040 12775.65 Mazar, Ope cit., map ref. 1712 1310, shows the

channel, but the aqueduct may have forked at somepoint further south, so that one branch led to Mamillaand the other straight towards the Upper City.

66 Possibly there was also a connection between theHigh and Low-level systems half a kilometre north ofMar Elias monastery, where there is a small pool atmap ref. 17040 12775, and a heavy line of masonrywhich almost stretches as far as the line of the low-level

channel at map ref. 175 127.67 Midrash Ekha Rabba on Lam. 4: 4.68 See C. Clermont-Ganneau, Receuil d'Archlologie

Orientale, Vol. IV (Paris 1901), 206-8, F. M. Abel, RB(1926),284-8, and L. Vetrali, LA 17 (1967), 149-61.

69 Josephus gives its length as fifty miles in War2. 175 and twenty-five in Ant. 18.60, which is inconclu-sive, since the High-level Aqueduct would have beennearer ten and the Low-level about forty.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 47which there are records of the number of citizens,70 but guesswork is the only guide to thenumber of inhabitants who did not have citizen status. Again, there are well-excavated Romancities like Ostia Antica 71 for which it is possible to calculate fairly accurately the amount ofliving accommodation, but we are still left to guess at the number who lived in each apartmentor room. Siagu is an excavated city in North Mrica for which both the city area and water-supply have been discovered, 72 but we cannot tell how much of the water was used for irrigationand how much for domestic consumption. 73 Similarly Byatt, after gathering the figures given byJosephus, is unable to offer us a total more precise than 'part population enumerated'. 74 It is,furthermore, a possibility that times of unusual prosperity on the one hand, or wars and famineon the other, may have caused rapid changes in population figures.

In the Holy Land comparisons between cities are exceptionally difficult, since we have nocities which have been as completely excavated as Ostia Antica, apart from those in theexceptional circumstances of the Negeb. But when we turn to Jerusalem we are on slightlyfirmer ground. The archaeological work of the last ten years has allowed us to form a generallycredible picture of the city area as it developed through six stages75 (see Figs. 1 and 10), andover the last century we have reached an overall understanding of the development of thewater supply which is accurate enough to be useful, even though many details remain obscure.Our advantage in studying Jerusalem is not, therefore, that we have precise figures for anygiven period, but that we can compare different periods, and relate development in area togrowth in water supply.

Before undertaking our calculations we must modify some of the assumptions we have sofar taken for granted. We have taken water consumption to have remained at the low rate oftwenty litres per head per day, and the population-figures in the last column of Table 2 (p. 51)are simply the number of people who could have been supplied with water at this rate. But weshould envisage a higher consumption per head, probably for the whole period we are consider-ing, and an increasing consumption both for public and private purposes in the progressivelyHellenised Jerusalem of Hasmonean and Herodian times. 76

Since we do not know the rates of consumption at any period, we have to make adjustmentson an arbitrary basis. For our final figures (set out in Table I) we have therefore worked on thebasis of a supply at the rate of twenty litres per head per day from the systems we have examined,but assumed the existence of cisterns which supplied extra water. We may reasonably assumethat most houses were equipped with cisterns, even though no excavations so far have coveredan area large enough to suggest their capacity. We can, however, calculate the amount of rainwhich would have fallen within the area of the city at any given period, and of this we shall

70 Thus Apamea in A.D. 6 had 117,000 citizens,GIL 111.6687(=H. Dessau, Inscriptiones Latinae Selectae,Berlin 1892-1916, 2683). R. P. Duncan-Jones, in hisarticle 'City population in Roman Africa', JRS 53(1963),85-90, reproduces Galen's statement that therewere 40,000 citizensin Pergamum in the second centuryA.D., and a report that in Autun there were 32,000 'freemen and women' in the time of Constantine.

71 J. E. Packer, 'Housing and Population in ImperialOstia and Rome', JRS 57 (1967), 80-89 suggested forOstia a maximum population of27,000 in a town madeup of insulae and occupying 69 hectares. See also hisstudy, The Insulae of Imperial Ostia and Rome, (Memoirsof the American Academy in Rome, 3I Bergamo 197I), esp.65-71.

72 See P. Grimal, 'Les Fouilles de Siga', Melangesd'Archeologie et d'Histoire de l'Ecole Franfaise de Rome, 54(1937), 108-41, and Duncan-Jones, op. cit., 86-88.

73 Duncan-Jones' estimate of about 17,000 personsin an area of 55 hectares seems low, since it involves adaily consumption of 530 Htres per head per day fordomestic use and irrigation. In fact it is impossible toevaluate this suggestion without knowing how muchwater was delivered in the city area.

74 Byatt, op. cit., 54.75 For growth between the Jebusite period and the

reign of Solomon see Kenyon, op. cit., especially29 and57; for the late monarchy N. Avigad, op. cit., with thet"evisedarea he proposes in Qadmoniot 5 (1972), 94 (onthe basis of wall I); for the Herodian period compareY. Aharoni and M. Avi-Yonah, The Macmillan BibleAtlas, (New York and London 1968),map 221; and forHerod Agrippa seeJ. B. Hennessy, Levant 2 (1970), 24.

76 Thus besides its bath Herod's Jerusalem palacegarden contained canals and 'pools everywhere',Josephus, War 5.168, 181.

1 KM.-- ---- ----J~~~r~~

~~, .•.-I--"~,.""~'",,~,~~~.

j~~~,

L- ....~~ •.~

~~~rt4t-~~ ..~rr I

~

\

I

" --,~, II"""C. IiiiiiiI, loot - t~ ,.- ~

17

7I

II

-I~ 7~.,.

~I

..'-

~----rIJ •/. I

"- 7 I~ I

....•..••.•... -,~ I......•••... 7

"'""'- --,--............ I----- -,

~

~ Area under Herod the Great.

_ Aelia Capitolina. eOVERLAP

Fig. 10. HerodianJerusalemUnder Herod Agrippa the walled city extended northwards to cover its maximum area. Thesouth wall of Aelia corresponded roughly with the line of the modern south wall.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 49assume that halfwas collected in cisterns. When we add this water to the twenty litres per headper day from the external systems we approach a more reasonable estimate of consumption.

It is hard to estimate the amount of water which was used for public purposes as opposed todomestic consumption. Here again we have adopted an arbitrary figure, on the basis of thefigures for Rome in the first century A.D. reported by Sextus Julius Frontinus. He tells us thatof the water delivered in the city 28 per cent was used for public works,77 and since this is thebest guide available we have deducted 28 per cent from all population-figures suggested fordates after 200 B.C.

It is hoped that the resulting figures, shown in the graph (Fig. 1I) and Table 1 (p. 50)appear generally credible. The probability that they are a fair indication of the developmentof the city is strengthened by the fact that the estimates of area are the results of archaeologicalwork independent of our own conclusions on the basis of the water-supply. At the end of theTable we have added figures for Jerusalem in 1918, since in that year the population of the OldCity (equivalent in area to Aelia Capitolina) reached the highest figure recorded in moderntimes. The inhabitants were then depending on cistern water alone, which provided them withabout sixteen litres per head per day, and frequently ran out.78

Area x 1.000 Sq.m.800

700

600

500

400

300

200

100

o

AREAGROWTH

J' ~ ~ ~ 9.~ ~~'li ~ ~v &fli &fli

§Q .SI:}~ #~tri :S~ 'S(b~ ~

;)<:::? ?f ~ #-.!!:~ J'\§! b~ vtri

')"8 ~ ~ ~o ~!!'?if .::! ~'lJ ~'lJ -f"

Fig. I I. Graph comparing development by Area and Water-supply.

77 Frontinus, de Aquis 78: 28 per cent represents hisproportion for munera and operapublica.

78 See the Royal Engineers' report in PEQ (1919),

14-27, and the valuable study (which they used) byG. Franghia, Projet sur l'Adduction des Eaux d'Arroub,(Constantinople 1912), 4.

5° PALESTINE EXPLORATION Q,UARTERLY

TABLE I-DEVELOPMENT

POPULATION AREA DENSITY CONSUMPTIONCEILING X Persons 20 litres andLess 28% 1,000 per addition fromafter sq. m. 1,000 cisterns per200 B.C. sq. m. head per day

JEBUSITES AND DAVID USING GIHON 2,5°0 5° 5° 36SOLOMON USING B. EL l}:AMRA 5,000 135 37 42LATER MONARCHY WITH ETAM

SYSTEM 10,633 410 26 52HEROD THE GREAT (EARLY) WITH

POOLS c.I-6 (TABLE 2) 36,280 41O? 88 27HEROD THE GREAT (LATE) WITH

SYSTEMS D-E (TABLE 2) 7°,398 615 114 27HEROD AGRIPPA WITH HIGH-

LEVEL AQUEDUCT 76,13° 895 84 3°AELIA CAPITOLINA

USING ALL SYSTEMS 76,130 705 108 28Jerusalem 1918 using cisterns only 36,000 7°5 51 16

CHECKING THE ESTIMATESScholars who have discussed the population-figures for ancient Jerusalem have received littlehelp from contemporary documents, which concern themselves mainly with exceptionalcircumstances.79 They have therefore based their estimates on other factors, such as density. 80

Our study of the water-supply thus suggests a supplementary method of narrowing the field ofconjecture, since it points towards a probable population ceiling at different periods. Of thesuggestions set out in Byatt's article we would therefore agree most closely with that of ProfessorJeremias, who proposes a population of about 55,000 in the city before the reign of HerodAgrippa, and a maximum density which, stated in the terms used in our Table, amounts to 52persons per 1,000 sq. metres.81 Using our own calculations as a basis we must regard Byatt'sown estimate of220,000 persons living in 'Jerusalem and environs (Bethany, Bethphage, etc.)'82as too high, for if we regard the majority of this number as resident within the walls ofJerusalem we discover that their consumption of water would have to have been at an im-probably low rate, less than ten litres per head per day.

During the past century several important elements in the water-systems of ancientJerusalem have disappeared beneath new housing estates. Dr Amichai Mazar has provided uswith a valuable up-to-date survey of the major aqueducts coming to the city from the south,and it is now to be hoped that the remains of the rain-collection system can also be surveyed,and, if possible, dated. Such work would not only correct and complement our rapid examina-tion of the Jerusalem water systems, but might also provide a useful means of measuring thedevelopment of Jerusalem from a 'good-sized village' to what Pliny called 'far the mostillustrious of the cities of the Orient'. 83

79 Number in the city at feasts (see J. Jeremias,Jerusalem in the Time of Jesus (London 1969), 77-84) orduring Titus' siege (seeByatt, op. cit, 57). Compare alsoJeremias, op. cit, 83, n.24.

80 See Byatt, op. cit., 58.81 Jeremias, op. cit., 83, n.24: note that Jeremias is

working on a different area for the city. The densitiesproposed for Siagu (39 per 1,000 sq. metres) and OstiaAntica (minimum 18, maximum 39) are thus con-siderably lower.

82 Byatt, op. cit., p. 56.83 Pliny, H.N. 5.14.

ANCIENT JERUSALEM: ITS WATER SUPPLY AND POPULATION 51TABLE 2-WORKING FIGURESWater figures are in cubic metres. Population ceilings are calculated at 20 litres per head per day.Capacities and areas are based on the sources mentioned on p. 43, n. 46.

Capacity INTAKE WASTAGE PRODUCT ADD TOs=spring IN POPULATIONr=rain Evaporation Leakage CITY CEILING

A. GIHON-spring s 73,000 2,500With B. el ~amra 2,500B. ETAM s 73,000Lower Pool (now) 90,000 9,558Aqueduct 7,720 20% 41,122 5,633c. POOLS BEFORE 25 B.C.:

I. MAMILLA (now) 119,200 r 102,750 5,586 12% 84,834 I 1,6212. N-W. AQUEDUCT r 59,400

Pool (?) 2,000?B. ~. el Batrak 20,600 3,160 15% 45,330 6,210

3. B. l}:USSEINI r 63,600 11,410Aqueduct 2,000 20% 62,910 8,618

4. B. ES SULTAN r 90,000Early Pool 58,400 5,840Aqueduct 700? 15% 69,960 9,584

5. PROBA TICA NORTH 8,100 r 23,400 1,080 10% 19,980 2,7376. STROUTHION 6,000 r 9,000 728

Aqueduct 12% 7,192 985D. 'ARRUB EXTENSION S 145,000B. 'Arrub 22,000 3,368Aqueduct 17,880Etam Mid. Pool 45,000 8,127 25% 79,285 10,861

E. B. EL MIYA'A 77,357 r 202,500 2,324Aqueducts 1,190B. If. S. Miriam 5,800 832Probatica South 31,760 2,640B.Isra'il 30,120 1,255 12% 169,779 23,257F. HIGH-LEVEL AQ. S 89,000Aq. half-covered 4,550Mar Elias pool 175B. es Sultan (now) 119,900 8,360 20% 57,115 7,961